Freezing methods are already known, which are implemented by freezing systems having the form of a conventional freezer in which racks are arranged horizontally, which are provided with locations intended to receive French straws previously filled with a certain volume of biological substance. As a variant, each French straw is introduced into a cylindrical or hexagonal tube, some of these cylindrical or hexagonal tubes are introduced into a beaker and several beakers are arranged vertically and stacked inside a canister that is itself arranged vertically in the freezer.
From the American U.S. Pat. No. 4,227,381 a system of freezing is also known, in particular of French straws filled with biological substance, provided with a cooling enclosure passed through by a flow of cooling agent entering this enclosure by an inlet duct and leaving this enclosure by an outlet duct. This enclosure has an internal space into which is introduced a single container, having a plurality of conditioning cases arranged in an ordered manner, i.e. aligned side by side and stacked, inside the container. In each conditioning case is arranged a French straw or an ampule previously filled with a volume of biological substance to be frozen.
The container, the cases introduced into this container as well as the French straws or ampules each filled with a volume of biological substance and introduced into these cases are arranged in the cooling enclosure in a direction similar to that defined between its inlet connector and its outlet connector.
The system is moreover provided with a unit for driving the cooling enclosure in rotation on itself. For this, the cooling enclosure is in mechanical inter-engagement allowing the driving in rotation at the level of its inlet connector. This cooling enclosure is also in mechanical inter-engagement allowing the rotation at the level of its outlet connector, which outlet connector is connected to an outlet duct for the flow of cooling agent.
In order to freeze the French straws, the cooling enclosure is set in rotation on itself and the flow of cooling agent flows along the closed container which comprises the cases each containing a French straw. The French straws are therefore driven in rotation whilst being held in the cases, which are held in the single container.